1. Field of the Invention
The present invention relates to a visual function examination apparatus for examining visual functions of eyes of an examinee.
2. Description of Related Art
Examinations of visual functions of examinee's eyes, for example, heterophoria measurement and the like, use optotypes which are placed at a predetermined distance (5 meters in general) from the eyes to be examined and are carried out by allowing the examinee to recognize those optotypes.
In recent years, in order to reduce space required for eye examinations, known is an examination apparatus which utilizes reflection by mirrors disposed inside a housing of the apparatus thereby to optically have a sufficient examining distance.
In such an apparatus, however, only optotypes can commonly be viewed inside of a housing which is dark as insulated from the outside. This causes a problem that a sense of distance is different from the case of recognition of optotypes actually disposed at a predetermined distance in a bright room, so that in the case of binocular examinations, binocular fixation may not be stable.
For example, optotypes for aniseikonia examinations may not allow fixation to fix at a desired position, and a figure which can be viewed by only a left eye and another which can be viewed by only a right eye are fused, as a result, accurate examinations of aniseikonia can not be achieved.